The present invention relates to a low pressure cryogenic refrigeration system for a vehicle cargo space and a method of operating the same.
Typically, to cool a vehicle cargo space, cryogens are evaporated in a cooling coil that is in thermal communication with a load space to cool the load space, and the cryogen is then released to the atmosphere. A cryogen storage tank must regularly be refilled in order to replace cryogen that is lost to the atmosphere. Additionally, conventional vapor compression refrigeration systems are sized to handle the peak demand on the system, such as initial pull-down from ambient conditions, pull-down immediately after a defrost cycle and after door openings. Therefore, refrigeration systems are typically larger than the size needed during normal operating conditions.